Pancreas cell. Coloured scanning electron micrograph (SEM) of an acinar (exocrine) pancreatic cell. Acinar cells secrete digestive enzymes to the small intestine, via the pancreatic ducts. The enzymes are secreted in vesicles known as zymogen granules (green). The enzymes are activated in the small intestine and aid the breakdown of carbohydrates, fats and proteins. Proteins are produced, packaged and secreted by the cell's endoplasmic reticulum (ER) and golgi apparatus (red). Magnification: x2300 when printed 10 centimetres high.